Colorectal and ovarian cancers represent a substantial source of morbidity and mortality in the U.S. The American Cancer Society (ACS) projects 2.1M new cancer diagnoses and 626,140 cancer deaths in the U.S. in 2026, and colorectal cancer, the second leading cause of cancer mortality, is projected to account for 55,230 deaths.1
While less prevalent than colorectal cancer, ovarian cancer is one of the deadliest gynecologic malignancies, projected to account for 21,010 new diagnoses and 12,450 deaths.2 Despite treatment innovation, five-year survival for distant-stage ovarian cancer – the stage at which nearly half of all cases are diagnosed – is just 32%.
Colorectal and ovarian cancers share the diagnostic challenge of nonspecific symptoms that commonly precede formal confirmation, often delaying clinical recognition and treatment. For patients diagnosed with colorectal or ovarian cancer, the 12 months preceding that diagnosis frequently involve a series of encounters for gastrointestinal complaints, pelvic pain, bloating or altered bowel habits, resulting in testing and treatment for conditions that may or may not be recognized as indicators of malignancy. The extent to which those encounters represent missed diagnostic opportunities, particularly among younger patients who fall outside conventional screening recommendations, is a question with direct implications for screening policies, clinical decision-making, disease advancement and mortality.
Colorectal cancer incidence among adults 65 and older has steadily declined since the Centers for Medicare and Medicaid Services (CMS) expanded screening colonoscopy coverage to all Medicare beneficiaries in 2001. Incidence rates in the Medicare population declined 4% to 5% per year through 2012, followed by more modest declines of 2.5% annually from 2013 to 2022.3 In contrast, the incidence of early-onset colorectal cancer (i.e., below age 50) has increased by 3% annually from 2013 to 2022. Early-onset colorectal cancer patients are more likely to present locally advanced (Stage III) or metastatic disease (Stage IV), in part because they are less likely to be captured by routine screening. Today, approximately one in eight new colorectal cancer diagnoses are in adults under 50.4 In response to this trend, the U.S. Preventive Services Task Force (USPSTF) lowered the initial screening age from 50 to 45 in 2021.5
Ovarian cancer is the leading cause of death from gynecologic cancer and the fifth most common cause of cancer death among women. With approximately 21,010 new diagnoses and 12,450 deaths projected in 2026, ovarian cancer’s case fatality ratio far exceeds its incidence rank.6 Five-year relative survival improved from 36% in the mid-1970s to 52% during 2015-2021 but remains below the 70% for all cancers combined over the same period. Late-stage diagnosis is the primary driver of poor outcomes, with 49% of cases diagnosed at a distant stage, for which the five-year survival rate is 32%, compared with 92% for localized disease. Five-year survival rates also differ by race, with a 44% survival rate for Black women as compared to a 51% survival rate for White women. Notably, the USPSTF assigns ovarian cancer screening a D recommendation, concluding with at least moderate certainty that harms outweigh benefits, as transvaginal ultrasound and CA-125 testing produce high false-positive rates that lead to unnecessary surgical intervention without a corresponding reduction in mortality.7 Therefore, diagnosis depends on symptom recognition and clinical judgment. The symptoms associated with ovarian cancer (e.g., bloating, pelvic or abdominal pain, early satiety, urinary urgency) are common in the general population and frequently attributed to benign conditions before cancer is identified. Women with ovarian cancer typically present to their primary care provider multiple times before a workup leads to diagnosis, a pattern more pronounced in younger women.8 Over the past decade, ovarian cancer mortality declined by 2.7% per year, while incidence declined at a 1% per year, a gap that reflects treatment advances and incremental shifts toward earlier-stage diagnosis rather than improved population-level detection.
This analysis examines the diagnoses recorded in the 12 months prior to an index colon or ovarian cancer diagnosis. Patterns in how frequently and how early related but nonspecific diagnoses appear in the pre-diagnosis window, and how those patterns vary by patient age, offer a population-level view of the diagnostic journey preceding cancer confirmation.
National incidence and mortality trends were characterized using delay-adjusted SEER incidence data and National Center for Health Statistics mortality data from 2000 through 2023, stratified by age group. Age groups were defined as early onset (less than age 50), older adult (50-64) and senior (ages 65 and older). All payer claims data were leveraged to analyze pre-diagnostic encounter patterns for colorectal and ovarian cancer patients between 2019 and 2024. Both cohorts excluded patients under age 18 and patients with any prior cancer diagnosis in the 12-month period preceding the initial cancer diagnosis.
For each age cohort, diagnoses rendered in the 12-month window preceding the index cancer date were analyzed using the related R (symptoms, signs, and abnormal clinical findings) and K (diseases of the digestive system) ICD-10-CM chapters for colorectal cancer and the R and N (diseases of the genitourinary system) chapters for ovarian cancer. The most frequently recorded diagnosis code conditions in the pre-period were ranked by age group for each cancer type. Additionally, the median time from first recorded pre-index diagnosis to the index cancer diagnosis date was calculated by cancer type and age group.
Colorectal cancer incidence and mortality trends from 2000 to 2023 differed by age group during the period. Among early-onset adults, incidence increased from 6.1 to 11.5 per 100,000 (88.5%) and mortality from 1.6 to 1.9 (18.8%) over the period (Figure 1). Among older adults, incidence declined from 85.0 to 80.3 (-5.5%) and mortality from 24.8 to 20.1 (-19.0%). Among seniors, incidence decreased from 304.7 to 159.3 per 100,000 (-47.7%) and mortality from 125.1 to 65.3 (-47.8%).
Ovarian cancer incidence and mortality also differed by age group during the period. Among early-onset adults, incidence increased by 14.3% from 4.2 per 100,000 in 2000 to 4.8 in 2023, while mortality declined from 1.2 to 0.7 (-41.7%) (Figure 2). Among older adults, incidence declined from 30.4 to 22.6 (-25.7%) and mortality from 15.6 to 9.2 (-41.0%). Among seniors, incidence fell from 51.9 to 34.3 (-33.9%) and mortality from 45.0 to 28.4 (-36.9%). Notably, among seniors the gap between incidence and mortality rates was narrow throughout the period – 51.9 vs. 45.0 per 100,000 in 2000 and 34.3 vs. 28.4 in 2023 – reflecting the poor prognosis of ovarian cancer at older ages and the high share of diagnosed patients who die from the disease.
Abdominal and pelvic pain, symptoms and signs involving the digestive system and abdomen and diseases of the anus and rectum were the three most frequently recorded pre-index diagnoses across all age groups in the 12 months preceding a colorectal cancer diagnosis (Figure 3). Gastrointestinal symptoms and functional disorders dominated the pre-index period regardless of age. The most notable age-related differences were in inflammatory bowel disease (IBD) and rectal diagnoses. Crohn's disease and ulcerative colitis ranked fourteenth and thirteenth among early-onset patients, but did not appear in the top 15 for older adults or seniors. Diseases of the anus and rectum ranked second among early-onset patients and older adults versus fourth among seniors. Malaise and fatigue ranked sixth among seniors but tenth among early-onset patients.
Abdominal and pelvic pain, noninflammatory disorders of the ovary, fallopian tube and broad ligament and symptoms and signs involving the digestive system and abdomen were the three most frequently recorded pre-index diagnoses across all age groups in the 12 months preceding an ovarian cancer diagnosis (Figure 4). The most notable age-related differences were in reproductive and gynecologic diagnoses. Endometriosis ranked tenth among early-onset patients, but did not appear in the top 15 for older adults and seniors, and menstrual irregularities appeared exclusively among early-onset patients. Abnormal findings on diagnostic imaging of other body structures appeared in the top 15 for older adults and seniors but not for early-onset patients, and among seniors and older adults, digestive symptoms ranked first rather than gynecologic diagnoses.
The median interval between first recorded symptomatic diagnosis and cancer confirmation was 60 days for colorectal cancer and 49 days for ovarian cancer across all ages. For colorectal cancer, the interval was longest among seniors at 67 days and shortest among older adults at 50 days, with early-onset patients at 53 days (Figure 5). For ovarian cancer, the interval was longest among early-onset patients at 60 days and shortest among older adults at 43 days, with seniors at 47 days. The longer interval among early-onset ovarian cancer patients relative to all other age groups is consistent with lower clinical suspicion for malignancy in younger women presenting with nonspecific symptoms. Diagnostic delay is an established contributor to ovarian cancer prognosis, with research finding that treatment delays of more than one month are associated with increased mortality risk, with one multi-cancer analysis estimating that risk increases by 6-8% for every month of delay.9
Both colorectal and ovarian cancers frequently present with nonspecific symptoms (e.g., bloating, abdominal pain, gastrointestinal complaints) that are easy to attribute to benign conditions, a dynamic that this analysis suggests is particularly consequential in younger patients in whom clinical suspicion for malignancy is lower.
For colorectal cancer, the pre-index diagnostic trends differed by age. IBD diagnoses (i.e., Crohn’s disease, ulcerative colitis) appeared prominently among early-onset patients but not seniors, and early-onset patients had a longer median interval to diagnosis than older adults. These patterns are consistent with lower cancer suspicion in younger patients and with the well-documented role of IBD as a colorectal cancer risk factor that skews younger. Concerningly, three in four early-onset colorectal cancer patients are diagnosed with advanced disease, including 27% with distant metastases.10
For ovarian cancer, the pre-index diagnostic trends among early-onset patients were dominated by gynecologic diagnoses (i.e., noninflammatory ovarian disorders, endometriosis and menstrual irregularities), consistent with a premenopausal patient population. Among older adults and seniors, pre-index trends were led by nonspecific digestive symptoms rather than gynecologic diagnoses, consistent with the postmenopausal profile of most women in this age group. In the absence of a recommended screening modality, earlier recognition of pre-diagnostic symptom patterns represents one of the few available pathways to improved outcomes – particularly for early-onset patients, who in this analysis faced the longest median interval to confirmed diagnosis. Diagnostic delay carries established prognostic consequences in ovarian cancer, with treatment delays of more than one month associated with increased mortality risk and one multi-cancer analysis estimating that risk increases by 6–8% for every month of delay.
The central finding across both cancers is that incidence is growing among early-onset populations without corresponding improvements in mortality. Much of the health economy is focused on the diagnosis and treatment of the disease. With respect to cancer, delays in diagnosis manifest in markedly worse outcomes, with the five-year survival differential between localized and distant-stage ovarian cancer is 92% vs. 32%; for colorectal cancer, it is 91% vs. 15%.
For that reason, a key challenge for health economy stakeholders is understanding how to diagnose cancer more quickly in the early-onset population. This population generally falls outside current screening recommendations for colorectal cancer, except those ages 45 to 49, while there is not a USPSTF screening recommendation for ovarian cancer. Ensuring that medical schools adequately prepare students to recognize subtle patient-reported symptoms as early indicators of undiagnosed cancer is an important consideration for the Association of American Medical Colleges (AAMC). Similarly, whether large language models (LLMs) can catalyze advancements in diagnostic technology, such as blood testing, would seemingly be an area of focus for the National Institutes of Health (NIH). With respect to colorectal cancer, why screening produces different results in reduced cancer incidence across age cohorts warrants further examination.
A more fundamental concern is understanding why certain cancer types are increasing in the early-onset population. Established risk factors for colorectal cancer include obesity, physical inactivity, alcohol consumption and dietary patterns associated with Western diets.11,12 Antibiotic use and gut microbiome disruption are areas of active investigation, and microplastics have been proposed as a contributing factor, though a causal link has not been established.13
Cancer spending in the U.S. reached $183B in 2015 and is projected to exceed $245B by 2030, with stage at diagnosis a material driver of that cost burden. In a health system with unsustainable cost trends, the most obvious way to reduce spending is to reduce disease incidence. Given the substantial resources directed toward curing cancer, greater policy action to prevent it is needed.